The precise role of neutrophils in adult respiratory distress syndrome is not yet clear. Endotoxin administration is known to induce the permeability pulmonary edema with neutrophil migration into alveolar spaces. Leukotriene B4 is known as a strong chemotactic factor. To clearify the roles of neutrophils on pulmonary microvascular injury, we compared the effects of endotoxin and leukotriene B4 on lung lymph dynamics and neutrophil migration. Endotoxin caused increase in microvascular permeability and migration of neutrophils into alveolar spaces.
Whereas leukotriene B4 did not affect lung microvascular permeability. Neutrophils in broncho-alveolar lavage fluid after leukotriene B4 administration increased to the same value as which after endotoxin administration. These results suggest that the neutrophil migration into alveolar spaces is not essential to develop the permeability pulmonary edema.
